9pnet: p9_fd_create_tcp (24969): problem connecting socket to 127.0.0.1 qnx4: no qnx4 filesystem (no root dir). ============================================ WARNING: possible recursive locking detected 4.19.211-syzkaller #0 Not tainted -------------------------------------------- kworker/u4:1/23 is trying to acquire lock: 00000000f54877be (&port_lock_key){-.-.}, at: uart_write+0x1ce/0x6f0 drivers/tty/serial/serial_core.c:591 but task is already holding lock: 00000000f54877be (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1876 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&port_lock_key); lock(&port_lock_key); *** DEADLOCK *** May be due to missing lock nesting notation 5 locks held by kworker/u4:1/23: #0: 00000000251a1b23 ((wq_completion)"%s""bat_events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 000000007099a491 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 00000000ce3d5625 (&(&i->lock)->rlock){-.-.}, at: spin_lock include/linux/spinlock.h:329 [inline] #2: 00000000ce3d5625 (&(&i->lock)->rlock){-.-.}, at: serial8250_interrupt+0x3a/0x240 drivers/tty/serial/8250/8250_core.c:115 #3: 00000000f54877be (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1876 #4: 000000009281c258 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:293 stack backtrace: CPU: 1 PID: 23 Comm: kworker/u4:1 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/26/2022 Workqueue: bat_events batadv_nc_worker Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_deadlock_bug kernel/locking/lockdep.c:1764 [inline] check_deadlock kernel/locking/lockdep.c:1808 [inline] validate_chain kernel/locking/lockdep.c:2404 [inline] __lock_acquire.cold+0x121/0x57e kernel/locking/lockdep.c:3416 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:152 uart_write+0x1ce/0x6f0 drivers/tty/serial/serial_core.c:591 n_hdlc_send_frames+0x278/0x470 drivers/tty/n_hdlc.c:403 n_hdlc_tty_wakeup+0xa0/0xc0 drivers/tty/n_hdlc.c:479 tty_wakeup+0xd4/0x110 drivers/tty/tty_io.c:534 tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:50 serial8250_tx_chars+0x490/0xaf0 drivers/tty/serial/8250/8250_port.c:1813 serial8250_handle_irq.part.0+0x31f/0x3d0 drivers/tty/serial/8250/8250_port.c:1900 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1873 [inline] serial8250_default_handle_irq+0xae/0x220 drivers/tty/serial/8250/8250_port.c:1916 serial8250_interrupt+0x101/0x240 drivers/tty/serial/8250/8250_core.c:125 __handle_irq_event_percpu+0x27e/0x8e0 kernel/irq/handle.c:149 handle_irq_event_percpu kernel/irq/handle.c:189 [inline] handle_irq_event+0x102/0x290 kernel/irq/handle.c:206 handle_edge_irq+0x260/0xcf0 kernel/irq/chip.c:800 generic_handle_irq_desc include/linux/irqdesc.h:155 [inline] handle_irq+0x35/0x50 arch/x86/kernel/irq_64.c:87 do_IRQ+0x93/0x1c0 arch/x86/kernel/irq.c:246 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:670 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:lock_release+0x429/0x8b0 kernel/locking/lockdep.c:3930 Code: 84 08 00 00 00 00 00 00 48 c1 e8 03 80 3c 10 00 0f 85 95 03 00 00 48 83 3d 7b 34 a6 08 00 0f 84 cc 01 00 00 48 8b 3c 24 57 9d <0f> 1f 44 00 00 48 b8 00 00 00 00 00 fc ff df 49 c7 04 04 00 00 00 RSP: 0018:ffff8880b5047b80 EFLAGS: 00000286 ORIG_RAX: ffffffffffffffd2 RAX: 1ffffffff13e3051 RBX: ffff8880b503c600 RCX: 1ffff11016a079db RDX: dffffc0000000000 RSI: 0000000000000003 RDI: 0000000000000286 RBP: 0000000000000002 R08: 0000000000000001 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff11016a08f73 R13: ef545f96172bec08 R14: ffff8880b503c600 R15: 0000000000000003 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:174 [inline] _raw_spin_unlock_bh+0x17/0x30 kernel/locking/spinlock.c:200 spin_unlock_bh include/linux/spinlock.h:374 [inline] batadv_nc_purge_paths+0x22d/0x310 net/batman-adv/network-coding.c:482 batadv_nc_worker+0x6fa/0xd50 net/batman-adv/network-coding.c:731 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 ---------------- Code disassembly (best guess): 0: 84 08 test %cl,(%rax) 2: 00 00 add %al,(%rax) 4: 00 00 add %al,(%rax) 6: 00 00 add %al,(%rax) 8: 48 c1 e8 03 shr $0x3,%rax c: 80 3c 10 00 cmpb $0x0,(%rax,%rdx,1) 10: 0f 85 95 03 00 00 jne 0x3ab 16: 48 83 3d 7b 34 a6 08 cmpq $0x0,0x8a6347b(%rip) # 0x8a63499 1d: 00 1e: 0f 84 cc 01 00 00 je 0x1f0 24: 48 8b 3c 24 mov (%rsp),%rdi 28: 57 push %rdi 29: 9d popfq * 2a: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) <-- trapping instruction 2f: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 36: fc ff df 39: 49 rex.WB 3a: c7 .byte 0xc7 3b: 04 04 add $0x4,%al 3d: 00 00 add %al,(%rax)